This brings back memories before it was archived in the sidetracked series. The cache was Thomas the tank engine. Unfortunately the Dartmoor Railway is no longer functioning but updates can be got on here https://www.dartmoor-railway-sa.org/
The headline co ordinates bring you to yellow water hydrant with three numbers on it = A B C
NB The other way point takes you to large sign. Ignore the logo and use the name.
Sum of second word = D
Sum of last word = E
CHECKSUM OF ABCDE = 22
The cache can be found at N 50° 46.(A+B) D (C+E)
W 3° 56. D A B